China has, over the past few years, taken numerous measures to strengthen what is referred to as the Great Firewall, legislative edicts designed at controlling the use of internet services in the country. After coming down hard with multiple laws outlawing the use of the VPNs used by individuals to circumvent the censorship measures taken by the government, and Just a month after a similar crackdown on VPN vendors, the government seems to now have blocked WhatsApp, one of the most popular messaging services in the world.

As The New York Times reports, the company had previously blocked, to differing degrees, the transmission of video, audio, and photos on the app, though the restrictions were lifted a few weeks later.

Now, Nadim Kobeissi, an applied cryptographer at Symbolic Software, a watchdog focusing on online censorship in China, reports that the use of text messages has also been blocked, completely restricting the use of the app in the country.

Kobeissi believes the move may have been a result of Chinese authorities figuring out how to block the NoiseSocket protocol used for text communication by WhatsApp. Video and other content are shared via HTTPS/TLS, which may indicate that the earlier stay on text messages was not necessarily an act of leniency but, rather, a stay of execution due to technical limitations which have now been circumvented.

With the shuttering of WhatsApp in China, none of Facebook's major services are available in the country as the social media site and Instagram were already banned, marking a significant setback for its ambitions in China, opening the gateway for local competitors like WeChat to take over the space.